基于实测的三相不对称电力系统谐波阻抗估计

通过分析星形和三角形连接下的三相不对称电力系统,推导建立了三相不对称电力系统谐波阻抗的矩阵估计模型。模型基于大量系统和负荷公共联接点处的实测数据,采用多元线性回归法,对系统侧的谐波阻抗矩阵各元素值进行估计。仿真实验及误差分析表明,所得模型是准确有效的。提出的方法数据获取简单、线性回归模型计算速度快,可用作实时估计。该研究结果可作为三相不对称情况下估计非线性负荷的谐波发射水平和配置谐波滤波器的基础工作。

Assessing Harmonic Impedance for Unbalanced Three-Phase Power System on the Basis of Recorded Data

In this paper,a versatile matrix model for assessing system side harmonic impedance of unbalanced three-phase power system is derived through the analysis on the two system models with different connections of star and delta.On the basis of recorded harmonic voltages and currents at the connection point of the load and the system,using multivariate linear regression,each value of the harmonic impedance matrix element is assessed to get the harmonic impedance matrix of this power system.Through the simulation experiments and error analysis on the results of assessments,the model is proved to be correct and effectual.Recorded data in the method proposed in this paper are easy to obtain.The computing rate of linear regression model is fast enough for real-time assessment.The results of this study may be used as the basic work in assessing the emission limits for nonlinear loads and also for sizing harmonic filters under unbalanced three-phase situation.